Balanced set of iron type golf clubs

ABSTRACT

A set of a plurality of at least a combination of three golf clubs of progressive lofts that are matched to provide identical swing characteristics; each of the golf clubs including a club head, a shaft and a grip at the upper end of said shaft; each club of the combination characterized by having an essentially identically located, computer designed center of gravity; each club being further defined by the shaft having an equal length, having an identical swing weight, identical grip weight and an identical club head weight.

BACKGROUND OF THE INVENTION

The present invention relates to iron type golf clubs and in particular to a balanced set of golf clubs.

The game of golf is played by a wide variety of different players having different physical and golf swing characteristics. Because of these differences traditionally conventional sets of golf clubs are balanced using a number of variables in order to fit the particular physical and swing characteristics of particular golfers. Such variables include things such as length of the club, the weight of the club, the flexibility of the shaft, the shape and size of the club head, the swing weight of the club and the location of the center of gravity using various weighting techniques.

All of these variables relate to the “feel” of the golf club as it is used to execute a golf swing to hit a golf ball to an intended target. Once the physical size of the club, such as length and weight, is determined, golf clubs are normally balanced by adjusting the swing weight of each of the clubs so they are matched throughout the entire set. The swing weight is a variable that relates to the way the mass of the club head is distributed in the club and how the club feels as the club is swung while executing a golf swing. The center of gravity is a parameter not usually matched in a set of golf clubs.

In the traditional method of balancing golf clubs, the clubs designed to hit a ball the farthest distances are longer than the clubs designed to hit the golf ball shorter distances. A shortcoming of this design is that the longer clubs are typically harder to use to make solid contact with the golf ball, primarily because the swing path or arc is longer.

Prior art golf clubs that have the same swing weight, same mass and same length are known in the art. It is a common practice to use wedges of the same length in a set of golf clubs.

An attempt to create a balanced set of golf clubs is disclosed in U.S. Pat. No. 3,984,103 to Nix which is directed to a matched golf club set wherein all clubs in a class of either irons or woods have equal shaft length, equal lie angle, equal swing weight and equal total weight. The Tommy Armour Company marketed a complete set of clubs that are the same size under the trade name Equalizers as has David Lake under the trade name 1 Irons. Neither the Nix patent nor the prior art products considered the location of the center of gravity when making clubs that were matched.

Another patent of interest is U.S. Pat. No. 5,624,329 to Schneebeli that shows matched putter and chipper golf clubs that are identical in weight, length, balance and feel.

SUMMARY OF THE INVENTION

The present invention relates to a combination of at least three or more golf clubs having varying loft designed to hit a golf ball different distances, the higher lofted clubs designed to hit a golf ball a shorter distance than the lower lofted clubs. Each of the clubs in the combination has the same length, swing weight and club head weight while maintaining a consistent center of gravity. The center of gravity is defined by the intersection of the horizontal (X), vertical (Y) and anterior/posterior (Z) axis often referred to as the actual center of gravity.

Each individual golf club of the combination of golf clubs in accordance with the present invention is made within the following tolerances while maintaining essentially identical characteristics. The designated loft of each individual club may vary plus or minus 1.0 degrees. The designated length may vary plus or minus 0.275 inches. The designated swing weight may vary plus or minus 1.0 swing weight points or 50 gram inches. The designated club head weight may vary plus or minus 5.0 grams. The resultant center of gravity may vary plus or minus 0.125 inches from its reference point.

The range of parameters for a combination of three or more consecutive golf clubs within a set is preferably the following: The lofts of the club head defining the ball striking face are between 15 and 65 degrees; the length of the club between 30 and 40 inches; the swing weight of the club between 5350 gram/inches and 6350 gram/inches; the club head weight between 220 grams and 370 grams and the vertical center of gravity between 0.50 inches and 0.90 inches, and the horizontal center of gravity 0.125 inches from the centerline of the ball striking face, and the anterior/posterior center of gravity 0.125 inches from its reference point of 0.15 inches behind the striking face.

An entire set may comprise up to a maximum of 12 consecutive irons lofted from 15 degrees to 65 degrees. The golf club combinations within a particular set may be a minimum of three consecutive clubs to a maximum of twelve clubs.

Among the objects of the present invention is a set of golf irons having at least one or more combinations of golf clubs having the same length, same weight, same swing weight and consistent center of gravity in each of the combinations of clubs in the set.

Another object of the present invention is a combination of at least three golf irons having the same center of gravity by adjustment of the physical size and shape of the club head.

These and other objects will become apparent with reference to the drawings and specification of the present application.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a set of golf club irons made in three combinations of three clubs in accordance with present invention.

FIG. 2 is an elevational view of three iron type, golf club heads forming a single combination of clubs of the present invention.

FIG. 3 is a rear elevational view of a single iron type golf club head of the invention.

FIG. 4 is a bottom view of the club head of FIG. 3.

FIG. 5 is a front elevational view of the club head of FIG. 3.

FIG. 6 is a top plan view of the club head of FIG. 3.

FIG. 7 is a toe perspective view of the club head of FIG. 3.

FIG. 8 is a heel perspective view of the club head of FIG. 3.

FIG. 9 is a toe end view of the club head of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS AND METHODS OF THE INVENTION

Referring to the drawings, FIG. 1 discloses a set of golf clubs 100 in accordance with the principles of the present invention. The set includes individual clubs 102 in three combinations 103 as represented by a first combination 103 a of the first three clubs 102 in the drawing, a second combination 103 b of the middle three clubs 102 and a third combination 103 c of the last three clubs 102. Each golf club 102 of the set includes a club head 104, shaft 106 and grip 108.

The overall length of each club 102 preferably is between 30 and 40 inches, the exact length being determined by the physical size and overall dimensions of the particular golfer who will use the clubs. In the embodiment shown, each club 102 of a first combination 103 a of the set 100 is made the same length of 38.25 inches within a tolerance of 0.275 inches. The second combination 103 b of three clubs 102 has a length of 37.25 inches also within a tolerance of 0.275 inches. The third combination 103 c of three clubs has a length of 36.25 with a 0.275 inch tolerance.

The swing weight of each club 102 in any of the combinations 103 of clubs is essentially the same and may vary plus or minus 1.0 swing weight points or 50 gram inches. Overall the swing weight is between 5350 gram/inches and 6350 gram/inches depending upon the physical characteristics and the individual swing of the golfer using the set of clubs 100.

The club head weight is the same for each club 102 of any of the combinations 103 of the set 100 and overall is between 220 grams and 370 grams and may vary plus or minus 5.0 grams.

The center of gravity is also essentially the same for each club 102 in a given combination 103 of the set. The Y-axis is located 0.50 inches to 0.90 inches from the bottom of the club head. The X-axis is located at the centerline of the club face. The Z-axis is located 0.15 inches posterior to the club face. The X, Y and Z axes may vary plus or minus 0.125 inches from its reference point.

FIG. 2 shows three club heads 104 of a typical combination 103 having different lofts of 29.5 degrees, 33.0 degrees and 36.5 degrees but with identical physical characteristics as described below.

FIGS. 3 through 8 show a typical club head 104 of a generally conventional design used in the golf set 100 of the present invention. It will be appreciated that all club heads 104 within the set 100 vary primarily in loft angle throughout the set 100 in a conventional manner. Each club head 104 includes a ball striking face 110, heel 112, toe 114, top ridge 116, bottom sole 118, and a rear peripheral weight 120, having a rear face 122, formed at an angle between said striking face 110 and rear face 122, the angle progressively increasing in a heel 112 to toe 114 direction. A rear cavity 124 is formed in the rear weight 122. The club head 104 further includes a hosel 126 for connection to a shaft 106 as shown in FIG. 1. The exact size and shape of the club head 104 is determined as described hereinbelow.

Each club head 104 is made as a single integral unit with all the club head parameters as described above precisely controlled using conventional forging, casting, CNC milling, 3D printing or other manufacturing techniques.

A preferable method of making a set 100 of matched golf clubs is described. The set includes at least one combination 103 formed of a plurality of at least three golf clubs 102, preferably with progressively increasing lofts, each having a club head 104, a shaft 106 and grip 108 to provide identical swing characteristics when using essentially the same golf swing.

The weight of each club head 104 and the location of the X-axis and the Y-axis are determined using four parameters; the height of the club at the heel and toe, the back angle between the front and rear surface of the club head, the back height and the cavity size. The back angle is used to determine the x-axis and the back height is used to determine the Y-axis as described hereinbelow.

Initially the weight of the club head 104, overall design and the center of gravity of each of the matched clubs 102 within a given combination 103 of the set of matched clubs are determined using a computer aided design program, CAD, and solid modeling, a technique within the CAD. The process includes the determination of the shape and size of the club head, including the determination of the X, Y, and Z axis.

The CAD measurements of the club head 104 are determined and the following steps are done in order to determine the exact parameters of the club heads 104 enabling each to be essentially identical to the others. Initially the height of the toe 114 and the height of the heel 112 are entered into the CAD program and a starting weight is calculated. The back angle is entered into the CAD program and a starting X-axis is determined. In the next step, the back height is entered into the CAD program and a starting Y-axis is determined. In the next step, the size of the cavity 124 is entered into the CAD program and a final weight is determined. The Z-axis is a result of the first four steps. Each of the steps may be repeated until an optimum, satisfactory result is obtained.

The toe and heel heights are consistent in size for each club 102 in a combination 103 within a set 100. The toe and heel heights are measured at a location equidistant from the centerline of the club head 104 on the ball striking face 110. The heights are varied to achieve the desired weight. By altering the toe and heel heights, the weight of the club head 104 can be increased or decreased. As the toe and/or heel height increases, the mass of the club head 104 increases. In like manner as the height of the toe and/or heel decreases, the mass of the club head 104 decreases.

The X-axis as seen in FIG. 3, is consistent in location for all the clubs 102 in a combination 103 within a set 100. To place the x-axis in a location on or very near the center of the ball striking face 110, the weight of the club head 104 is increased or decreased toward the toe 114. The weight is controlled by adjustment of the back angle shown in FIG. 4 of the width of club head 104 between the ball striking face 110 and the rear face 122, preferably at or adjacent the ground plane at the bottom sole 118. This back angle is measured in a direction from the heel 112 to the toe 114. By altering the back angle, weight can be distributed in both directions toward the heel 112 or toe 114 on the x-axis toward or away from the center of the club face 110. As the back angle becomes progressively larger, the mass of the club head 104 increases toward the toe 114 and the location of the X-axis shifts toward the toe 114 of the club head 104. In like manner as the back angle decreases, the mass of the club head 104 decreases and the X-axis shifts toward the heel 112. A shift of the location of the X-axis coordinate alters the location of the center of gravity CG of the club head 104.

As seen in FIG. 3, the Y-axis is consistent in height for all clubs 102 in a combination 103 within a set 100. In order to place the Y-axis in a location consistent with traditional clubs made in the golf industry at the present time, the mass of the club head 104 is raised or lowered by changing the back height of the rear peripheral weight 120 at the rear of the club head 104. By altering the back height, the mass of the club head 104 can be repositioned up or down the Y-axis. As the back height increases, the mass of the club head 104 moves up away from the bottom sole 118 toward the top surface 116 thereby moving the Y-axis up. In like manner, as the back height of the club head 104 decreases, the mass of the club head 104 moves down toward the bottom sole 118 and the location of the Y-axis moves down. A shift of the Y-axis upwardly or downwardly alters the location of the center of gravity CG of the club head 104.

The size of the cavity 124 is consistent in size for each combination 103 of clubs 102 in a set 100. The cavity 124 is measured by the major transverse axis, MITA, as shown in FIG. 3. The size of the cavity 124 is varied to achieve the desired overall weight. By altering the MATA and/or the MITA, the overall weight and mass of the club head 104 can be increased or decreased. As the MATA and/or the MITA increases, the mass of the club head 104 decreases. In a like manner, as the MATA and/or the MITA decreases in size, the mass of the club head 104 increases. The club head 104 is designed whereby the thickness of the striking face remains consistent throughout the entire golf club set 100.

The Z-axis coordinate is a result of the height of the heel 114 and toe 112, the size of the cavity 124, the weight and thickness of the club head 104 and the determination of the Y-axis. In this manner, the Z-axis coordinate is consistent in each combination 103 within a set 100. In each of the clubs 102 of a combination 103, the location of the Z-axis ultimately determines the location of the CG of the club. In the present invention the CG of each of the clubs 102 in a combination 103 is positioned an equal distance behind the ball striking face 110 no matter what the loft of the club head 102 in the combination 103.

Table 1 discloses typical measurements of various parameters of three combinations 103 of golf clubs 102 the make up a set 100. The table quantifies the center of gravity, CG, the toe and heel heights, the club head weight, the grip weight, the shaft weight, the shaft length, the total length, the cavity parameters, the back angle and the back height of the club head.

TABLE 1 20.5 23.5 26.5 29.5 33 36.5 40 44 48 CG X Axis Inches 0.05 0.05 0.04 0.04 0.04 0.03 0.05 0.05 0.05 CG Y Axis Inches 0.71 0.72 0.72 0.70 0.70 0.69 0.67 0.66 0.64 CG Z Axis Inches −0.19 −0.17 −0.17 −0.16 −0.15 −0.14 −0.13 −0.12 −0.11 Head Weight grams 252.0 252.0 252.0 268.0 268.0 268.0 285.0 285.0 285.0 Grip Weight grams 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 Shaft Weight grams 125.0 125.0 125.0 121.0 121.0 121.0 117.0 117.0 117.0 Shaft Length inches 37.07 37.07 37.07 36.07 36.07 36.07 35.07 35.07 35.07 Total Length inches 38.25 38.25 38.25 37.25 37.25 37.25 36.25 36.25 36.25 Major Tran Axis Inches 2.48 2.48 2.48 2.48 2.48 2.48 2.48 2.48 2.48 (MATA) Minor Tran Axis Inches 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 (MITA) Cavity Area Sq In 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 Back Angle degrees 6.25 6.25 6.25 6.25 6.25 6.25 6.25 6.25 6.25 Back Height Inches 0.61 0.61 0.60 0.56 0.55 0.54 0.50 0.49 0.48 Toe Height Inches 2.01 2.01 2.01 2.13 2.13 2.13 2.44 2.44 2.44 Heel Height Inches 1.06 1.06 1.06 1.18 1.18 1.18 1.30 1.30 1.30

Once the center of gravity of the club head is determined, the club head is formed using the conventional techniques briefly described above. The shafts are cut to matching lengths so each club in the various combinations 103 of the set 100 is of equal length. The shafts 106, grips 108 and the club heads 104 are measured for weight. The next step is to assemble the club head in a conventional manner by securing the shaft 106 to the club head 104 and finally attaching the grip 108 to the upper end of the shaft 106.

The present invention is not limited to the specific golf club heads disclosed and it is equally applicable to club heads of various designs and shapes. It will also be appreciated that other modifications can be made to the combinations of golf clubs disclosed above in keeping within the spirit and scope of the invention as described in the following claims. 

1. A method of making a set of matched golf clubs in combinations of at least three matched golf clubs; each club having a club head, a shaft and grip to provide identical swing characteristics; said club head having a means for connection to a shaft, a frontal ball striking face, a top surface, bottom surface, heel, toe and rear surface defining a rear weight and cavity formed therein, comprising the steps of: determining the precise location of the center of gravity relative to said frontal ball striking face of each of the club heads of a given combination of club heads of said set using a computer aided design program to insure said center of gravity is in the same relative position in each club head; measuring the weight of each of said club heads and adjusting the weight of each to insure the weight is the same; matching the length of the shaft of each club whereby the length is the same; and, attaching said shaft to said club head whereby each club has an identical length, identical weight, identical swing weight and identical center of gravity location.
 2. The method of claim 1 wherein the location of said center of gravity and said club head weight are adjusted by precisely adjusting the weight of said club head in accordance with parameters determined by said computer aided design.
 3. The method of claim 2 further defined by adjusting the X-axis, and the Y-axis of the location of said center of gravity in sequential steps.
 4. The method of claim 3 further including the step of adjustably positioning the x-axis of said center of gravity in a heel to toe direction by angularly varying the thickness of said rear weight of said club head in a heel to toe direction such that an increase of the angle of thickness locates the x-axis closer toward said toe and a decrease of the angle of thickness locates the x-axis closer toward said heel of said club head.
 5. The method of claim 4 further including the step of adjustably positioning the y-axis of said center of gravity in a top to bottom direction by adjusting the height of said rear weight between said top surface and said bottom surface such that an increase in height of said rear weight locates the y-axis closer toward said top surface and a decrease in height of said rear weight locates the y-axis closer toward said bottom of said club head.
 6. The method of claim 5 wherein the location of the z-axis of said center of gravity is a result of the position of the x-axis and y-axis.
 7. A method of adjusting the position of the center of gravity of a golf club head having a means for connection to a shaft, a frontal ball striking face, a top surface, bottom surface, heel, toe and rear surface defining a rear weight and cavity formed therein comprising the steps of: adjustably positioning the x-axis of said center of gravity in a heel to toe direction by angularly varying the thickness of said rear weight of said club head in a heel to toe direction such that an increase of the angle of thickness locates the x-axis closer toward said toe and a decrease of the angle of thickness locates the x-axis closer toward said heel of said club head; and, adjustably positioning the y-axis of said center of gravity in a top to bottom direction by adjusting the height of said rear weight between said top surface and said bottom surface such that an increase in height of said rear weight locates the y-axis closer toward said top surface and a decrease in height of said rear weight locates the y-axis closer toward said bottom of said club head.
 8. The method of claim 7 further including the step of varying the size of said cavity to further ad just the weight of said club head and said position of said center of gravity.
 9. A combination of a plurality of at least three golf clubs of progressive lofts that are matched to provide identical swing characteristics; each of the golf clubs including a club head with heel, toe, top and bottom surface, a ball striking face, a shaft and a grip at the upper end of said shaft; each club of said combination characterized by having a computer designed center of gravity located equidistant from said ball striking face; each club being further defined by the shaft having an equal length; having an identical swing weight, an identical grip weight and an identical club head weight.
 10. The combination of golf clubs of claim 9 wherein said center of gravity is defined by the location of a rear weight behind said ball striking face.
 11. The combination of golf clubs of claim 10 wherein said rear weight is further defined by an angular rear face progressively thicker toward said heel of said club head.
 12. The combination of golf clubs of claim 10 wherein said rear weight is further defined by a variable height between said top and bottom surface.
 13. The combination of golf clubs of claim 10 wherein said rear weight is angular in an x-axis direction between said heel and toe and said rear weight is variable in height between said top and bottom surface. 